H.265 rate control method for improved R-lambda model

Abstract

The invention relates to an H.265 rate control method for an improved R-lambda model. The method comprises the steps that firstly, relevant parameters of the rate are initialized, and for current coding frames, the variance, the absolute error and the SAD value of each image are calculated; secondly, bit allocation at the GOP level is conducted according to the JCTVC-K0103 proposal, and the absolute errors and the SAD values are compared; thirdly, a key frame, namely an I frame is inserted, the relevant coding parameters of the rate are reset, coding is conducted in an I frame rate control mode, and then coding of the current frame is ended; finally, bit allocation at the picture level is conduced, and the relevant parameters of the rate are updated according to the improved type. According to the H.265 rate control method for the improved R-lambda model, at the same rate, the video quality is remarkably better than that obtained through an existing method, and the image quality is remarkably improved.

Description

technical field [0001] The invention relates to an improved R-λ model H.265 code rate control method, through the detection of video sequence scenes and motion conditions, fully considering the different characteristics of video sequences, according to the different characteristics of video sequences and the previous video sequence Modify the α and β parameters of the R-λ model according to the relationship between scenes or motion changes, adjust the bit allocation, and improve the coding performance of the rate control. Background technique [0002] H.265 / HEVC (High Efficient Video Coding) is a new generation of international video compression standard, which is another major breakthrough in video coding standards after H.264 / AVC. Compared with 264, the video coding effect is in the case of the same image quality (PSNR), the bit rate is saved by 40-50%, but the algorithm complexity is increased by hundreds of times. [0003] Bit rate control plays an important role in vid...

AI Technical Summary

Problems solved by technology

Since more and more flexible modes are supported in H.265, it is more difficult to apply the rate control algorithm of Q-domain in H.265

[0007] 3) Since quantization is only valid for residual information, it is difficult to accurately model the relationship between non-residual bits and QP

[0009] 5) QP can only select integers, and for H.264 / MPEG-4AVC and H.265, the quantization step size doubles when QP increases by 6

[0022] In the above process, when there are frequent scene switching in the video sequence or the first dozens of frames are all black video frames, and the current frame is a scene with intense motion, the current frame will consume all the bits of the sliding window.

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